The goals of the proposed research are to examine the risk of mortality from lymphopoietic, hematologic, and gastrointestinal cancers and sarcomas from occupational exposure to butadiene and styrene and to determine if a dose response exists. Butadiene is the 36th most common chemical produced in the U.S. (IARC 1986). It is used in the making of plastics, resins, rocket fuels and rubber and rubber products. Animal studies suggest that the chemical is carcinogenic -- at different sites depending on dose -- and it also has the unusual property of activation of retroviruses. These features need to be investigated further in humans since the studies of the human experience related to butadiene exposure are still preliminary. Our earlier studies of workers in the styrene-butadiene polymer manufacturing industry showed an association between leukemia and exposure to butadiene (independent from exposure to styrene). This proposed research would expand that study by: 1) developing exposure levels of butadiene and styrene for each job in the industry based on actual area and personal monitoring rather than on the previously developed estimates of exposure made by industry personnel; 2) expanding the number,of cases of lymphopoietic and hematopoietic cancers and other cancers by adding cases from workers with short duration of employment but potentially high exposure levels; 3) identifying workers who died with gastrointestinal cancers and sarcomas and abstracting work history information; 4) selecting new controls matched for plant of employment, age, and date of hire but not for duration of work from the established cohort of workers and abstracting work history information for the new controls; 5) evaluating by case-control analysis the risks of leukemia, other lymphatic and hematopoietic cancers, gastrointestinal cancers and sarcomas associated with styrene and butadiene based on the newly developed exposure level.